Vacuum-plenum pneumatic-carrier-despatch system.



A. W. PEARSALL. VACUUM PL ENUM PNEUMATIC CARRIER DESPATCH SYSTEM.

APPLICATION FILED DEC-3| 1914.

Patented Sept. 18, 1917.

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ALBERT W. PEARSALL, OF LOWELL, MASSACHUSETTS, ASSIGNOR TO THE LAMSON COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF NEVI JERSEY.

VACUUM-PLENUM PNEUMATIC-CARRIER-DESPATCH SYSTEM.

Specification of Letters Patent.

Patented Sept. 18, 1917.

Application filed December 3, 1914. Serial No. 875,242.

To all whom it may concern:

Be it known that I, ALBERT V. PEARSALL, a citizen of the United States, residing at Lowell, in the county of Middlesex and State ofMa'ssachusetts, have invented certain new and useful Improvements in Vacuum Plenum Pneumatic Carrier Despatch Systems, of which the following is a specification. a

This invention relates to pneumatic carrier despatch systems and more Pitl'tlClF larly to a system of this character in which carriers are transmitted outwardly from one station to a second by means of compressed air while carriers are reversely transmitted from said second station to the first by suction or vacuum, so called.

The invention has for one of its objects the provision of means for economizing the power needed for the operation of such apparatus; and this is preferably effected by means of a novel valve mechanism which is adapted to simultaneously control the flow of air through both the outgoing and return tubes of a given one of said stations.

This and other objects of my invention will be hereinafter referred to and the novel combinations of elements whereby said ob jectsmay be attained will be more particularly pointed out in the claims appended hereto. Y

In the accompanying drawing which forms a part hereof and in which like reference characters designate like parts throughout the several views, I have exemplified a preferred embodiment of my invention; but as I am aware of various changes and modifications which may be made herein without departing from the spirit of the invention, I desire to be limited only by the scope of said claims.

Referring to the drawing:-

Figure 1 is a side elevation of a pneumatic despatch system constructed in accordance with my invention.

Fig. 2 is a detail vertical median section of a valve mechanism which forms a part of said system, and

Fig. 3 is an end elevation of the parts shown in Fig. 2.

In Fig. 1 two stations are shown, respectively designated A and B, and the outgoing and preferably normally dead tube from station A, which leads to station B, and through which carriers are transmitted by means of compressed air, has been desig nated 1.

' The preferably normally dead return tube from station B to station A and through which carriers are transmitted by vacuum, as it is loosely expressed, has been designated 2.

The expression normally dead as used in connection with or when referring to the transit tubes, is one in common use in the art and defines that said tubes are normally under or subjected to neither pressure nor vacuum, the air therein, when not in use, being at atmospheric pressure. This type of system, by the Way, is much less wasteful of power, since in long lines, especially, there is almost certainly, after a lapse of time, even when installed with great care and at a consequent increase in cost,-more or 1 ss leakage of air at the joints, etc.

The terminals 3 and 4: at stationB are both preferably normally open to the atmosphere while at station A the receiving terminal 5 is normally closed by a valve 6, and the delivering terminal 7 is normally closed by a leather flap valve, or the like designated 8.

The terminal 7 with its receiving shelf 9 is preferably of the type shown, such parts being in common use in exhaust or vacuum carrier despatch systems. The air is exhausted from the transit tube 1 and terminal 7 through an exhaust conduit 10 which is adapted to be placed in communication with a chamber 11 on the left hand end of a casing 12.

The port 13 through which the air emerges from the conduit 10 into said chamber 11 is controlled by a valve 1%, which also controls a port 15 through which the air in chamber 11 passes to a pipe 16 which leads to a vacuum drum 17.

Air is exhausted from the latter through a pipe 18 of preferably large diameter in order that a plurality of sets of transit tubes 1 and 2 may be operated from a common blower 19 into the intake side of which the pipe or conduit 18 extends.

The pressure side of this blower has correspondingly connected thereto a large pipe 19 which leads to a pressure drum 20, to

which in turn pipes'21.

The flow of compressed air from a pipe 21.is controlled by a valve, 22, preferably very similarin construction to the valve 1 1; valve 22 normally covering the port which when open permits the air to flow from pipe 21 into a chamber 24 between valves ltand 22.

When valve 22 is in its open position the air escapes from chamber l lthrou'gh a port 25 and via a pipe 26 to the ,desp'atching terminal 5. r

. Valves 14 and 22 are fixedly mounted with respect to each other, upon a hollow spindle or shaft 27 and these valves are. hence slidably movable together from the position in which they are shown in full lines in Fig. 2 to their dotted line positions, in-the direction of their common axis when shaft 27 is moved to the right. r,

The left hand end of this shaft is threaded are connected one or more into a cup 28 the flange of which normally treinities rod 31 is preferably reduced to pro' vide an air passage 33 therearound and a hole 3& 1s formed in the left hand end of shaft 27 to afford communication between thispassage 33 and the chamber 11, above referred to; while correspondinglya hole 35, just beyond the valve 22, places passage 33 in communication with a chamber 36, one wall of which is formed by said valve 22 and an opposite wall of whichis formed by a diaphragm 37. I

In addition to the openings 3% and 35, a groove or slot 38 is cut in lengthwise through the right hand head or end of the rod 31, said head being also turned down as at 39 to facilitate the free flow of air past the valve 32 when the latter is in its open position. 1 r I As shown in Fig. 2 the walls of the chamber 36 are preferably made a part of the casing 12, but the dome-like cap or head 40 at the righthand end of said casing is preferably made readily removable from the 1 casing in order to permit of access to the latch and toggle parts in chamber 36, here inafter referred to, and in order to permit of the ready insertion or removal of the diaphragm 37, which is clamped between the flanges of the casing 12 and dome 40.

The chamber 41 to the right of the diaterior of the valve 22; the latter being prefphragm 37, is preferably made as large as practicable for reasons hereinafter indicated, and a readily opened flap valve 42,. of flexible leather or the like, covers a hole 43 through which the air. in dome 41, even if but slightly compressed above atmos- 7O pheric pressure, may escape A small passage 44: nearly closed by a timing valve l5 permits of a slow seepagev of air through, for example, a passage or hole 16, which communicates with passage 44:, into the chamber 41, when a partial vacuum has been formed in the latter.

Slidably mounted upon the right. hand end of the tubular shaft 27 is a sleeve 4:7 which is preferably flanged as indicated, at 86 its right hand extremity, to adapt it for engagement with the central portion of the diaphragm 37 to ,the'e'nd that said diaphragm shall not be cut thereby, but rather may flex around a smoothly curving surface. Upon the other side of the diaphragm is a dished plate 48, correspondingly adapted for engagement with said diaphragm; the flange of the sleeve 17, diaphragmand said platel8 being all riveted together as at 49.

It is also preferred to'pr'ovide lugs 50 in the interior of the dome, against which the dish 48 may come to rest. Sleeve 47carries lugsv pivotally connected to which at 51 are links 52, which constitute elements 5 of the toggles hereinafter referred to. I

Preferably upon opposite sides of the chamber 36 arerecesses 53 within which are pivoted as at 54;, latch elements 55; said elements preferablybeing secured to the pins upon which they are mounted so that the latter rotate with said elements, and each of said pins having connected thereto a. spring 56 which tends to hold the latch parts in their full line positions, as shown 1 in Fi 2.

,AdJustable stops 57 are also preferably provided to limit the outward swing of the latches, and thereby to maintain out of dead center, the respective sets of pivoted pins 51 and 54 and the pin 58 which connects eachlink 52 with the rearwardly project ing arm of the corresponding latch element. It is also preferable to provide slots in the links 52 in which ride these pins 58, as indicated in said figure.

The left hand ends of the latch elements 3 are adapted for engagement with an annular rib 59 which extends around in the. in-

erably hollow as shown. A helical spring 60, disposed around the right hand end of the shaft 27 normally urges said shaft, and thereby the valves 22 and 1% mounted thereupon, toward their left hand positions, in which said valves close the ports 13, 15, 23 and 25; the other extremity of this spring bearing against, the edge of the sleeve 47 and driving. the latter, together with diaphragm 37, and dish 48 toward their right hand positions.

The lugs 50, above referred to, serve to limit this movement of the sleeve and diaphragm, while, as previously stated, the cup 28 aflixed to the other end of shaft 27 limits the left hand movement of the valves and shaft by engaging the cap or. cover plate 29.

This cover plate has screwed thereinto a I pipe or nipple61 which may be placed in communication with a pressure supply pipe 62 by opemng a valve 63 1n the manner hereinafter described.

The pipe 62 preferably extends to a tank 64 which may be filled with compressed air, and when valve 63 is opened compressed air escapes from said tank into the space between the piston 30 and cap 29, thereby driving saidpiston together with its rod 31, to the right. I

s A relatively weak spring ineffectively resists this movement and tends to return said piston to its left hand, position as soon as the pressure upon said piston is relieved.

The right hand movement of piston 30 first opens the valve 32 and thereafter drives the shaft 27 with its attached parts to the right. This opens theports 13, 15, 23 and 25 and causesthe latch elements 55 teengage the valve 22 whereby to lock both valves in theiropen positions.

Compressed air now flows from pipe 21 through chamber 24 into pipe26, while the air in the pipe 10 becomes rarefied as it escapes via chamber 11 and pipe 16 to the vacuum drum 17.

The partial vacuum thus formedin chamber 11 causes a flow of air past the open valve 32 from the chamber 41 in the dome,'through the slot 33, passage 33 and hole 34 into said chamber 11, and thence out through pipe 16 until the pressure of air in chamber 41 has been reduced substantially to that in the exhaust conduit 10. r p r Further, owing to the fact that the chamber 36 is also in communication with the passage 33, the air upon the left hand side of the diaphragm 37 will also be partially exhausted, so that the pressure upon opposite sides of said diaphragm will be substantially equal.

As soon as the. valve 63 is permitted to move to its closed position, the compressed air supply to the pipe 62 is of course cut off and the air under pressure to the left of piston. 30 .thereupon escapes through the opening 66, whereupon spring 65 returns the piston to its left hand position and closes the valve 32. I

Now, while chamber. 36 is, still incommunication with the exhaust, chamber 41 no ,longer has air exhausted therefrom, while air slowly seeps into said chamber past the timing valve 45. I

The advantage of providing a large chamber,4l is now apparent since it will take considerabletime for, this chamber to fill with air at a pressure sufficiently above that in chamber 36 to drive the diaphragm with its attached sle'eye 47 to the left against the action of the compressed spring 60.

Had the chamber 41 been located in a receptacle which would quite closely conform to'the diaphragm 37, when the latter is in its righthand position, as is quite common practice in pneumatic timing devices used in pneumatic despatch apparatus, it is evident that air at a sufficient pressure to op- ,eratively displace the diaphragm. would quite speedily be accumulated; and hence I particularly desire to direct attention to this provision of the commodious chamber 41 since thereby a timing period of relatively great duration is secured.

, This lengthy timing of the closure of a valve for controlling the flow of air through a transit tube is frequently of great importance and especially when the lengthof the line is considerable. Then the diaphragm 37 finally does he gin to move toward the left, at first its .movement is idle but as soon as the'pins 58 are seated againsttheinner ends of the slots in which they ride, the latch elements 55 begin to rotate toward their dotted line positions, whereby to release the valves 14 and 2 2. l p i i As soon as these latches clear the rib 59, said valves are abruptly closed by the action of spring 60, whereupon the exhaust ofair from chamber 36 ceases, and said chamber 36 is placed in communication with the atmosphere by the removal of the valve 22 from its position above a port 67. permitting spring 60 to. drive the diaphragm to the right; the air in chamber 41 being brought to atmospheric pressure through the, opening of the flap 42.

- I shall now consider the'preferred mode of operating the valve 63, which is preferably of the balanced type. The stem 68 of this valve is preferably of iron and extends A up into the solenoid 69, which when energized by current from the battery 70 has suflicient strength to lift said .valve to its open. position. At station A, the spindle upon which is mounted the valve 6 carries a contact 71' which-is rotated into engagement with a contact 72 each time that the valve is raised by theinsertion of acarrier into the terminal. 7

Current thereupon flows from the battery through a wire 73 to the solenoid 69 and from thence through a wire 74 to contacts 72 and 71, whence it flows via wires 7 5 and 76 back to the battery.

"pleting the following circuit:

Solenoid '69 may also be controlled from station B by means of the usual contact operating arm 77 located in the path of the carrier adjacent 'th'emouth of the terminal 3 which effects a closure'of circuit in the contact box 7 8, 1n known manner, comterminal.

Should the valves '14: and 22 be in their open positions and latched by the elements 55, when a second carrier is to be despatched from one or the other of the stations, the'effect of this second opening of valve 63 before the return of the shaft 27 to its le'ft hand position, 'is to momentarily again open the 'valve 82 by the inward movement of the piston 30 into its cup; whicheflects an equalization of pressure upon opposite sides o f'the diaphragm 37, the air already accumulated in the chamber 41 "passingthrough the slot 38, passage 33 andjopening 34, into chamber 11.

patched; shown a panel 82, and somewhat diagrammatically the 'electricconnectlons to the mo- The motor 81 whichdrives the blower 19 my be a continuously driven one and indeed where a number of transit lines "are connected with the drums "17 and 20 and wh'ere asa result the motor is of'r'elatively large size as compared to that required for operating a'single line of transmission tub- 111g, avoid the loss incident to starting it from time to time, whenever a carrier is des- To "the right of 'the'blower is tor; the diagram of the armature and shunt winding being thus shown in order to avoid multiplication of figures. This panel comprises a shunt field rheostat 83 controlled by an arm 81 pivoted upon the panel at 85.

The left hand end of the rheostat arm carries a bracket upon which is mounted a roller 86, which is adapted to ride upon a small table 87 carried upon the upper end of'a rod 88. This rod-has secured'thereto a piston 89 which ridesin a cylinder 90'and suitable weights '91 are attached to the lower extremity of said rod. i I

Theupperend of the cylinder 90 is con- -nec'ted by a pipe 92, preferably but of course "not necessarily, with the exhaust conduit '18,.so that when the valves .14: and 22 are closed, a sufficient vacuum will be established in theupper end'kif the cylinder 90 it should be continuouslyoperated to sense to 1101 d. the piston'i it npperm-ost position against the action of the weights "91-. v v

v This of course will hold the arm-sa in -t'he li iting position into which it can be 1-0.-

tated clockwise, thereby cutting resistance out of the shunt field -93""00 reduce the-speed of the motor toaini-nimum. c i

h 'Whenever 'valves 14 and 22' are opened, however, the vacuum the conduit 18 is partly broken and the piston 89 descends a distance corresponding substantially to the rise in pressure upon the exhaust side of the blower; This actiQnpermitS the arm 84,

weigh-ted as it "is bythe bracket'which carrice the roller 86, to rotate "counter-clockwise to out in resistance infthe shunt field and -correspondingly speed 'uplthe motor to a 'i'ea'ter'or-less amount. 7

t is obvious that if but a single 'line of transit tubing has been thrown into opera "tion, the speed of the motor will be increased but the requisite amount to operate "such line, while if -a'jplurality of the lines which are in communication with drums17 and 20 are simultaneously thrown' into operation, the'speed (if-the motor will rise to meet such condition.

The electrical circuits controlled by the respective parts mounted upon this panel board need not be "herein-further discussed "since boards of this description are in common use. i i

Accordingly reference will merely briefiv be made-to certain of the wires and parts to identify the same. The leads to the armature have been designated 94' and 95 and the ends'of these'leads are shown by dotted lines extending from the motor-as wellas in full 'lines in the wiring dia 'g' ram. The

part designated 96*i's-the resistance which is r cut out ofthearmature circuit whenthe mo- ;tor is started'by means of the startingleve'r '97, and the devicedesigna'ted 98i's the elec- "tro-niagnetic' latching device for holding the starting arm inits right hand position as long as the motor continuesin operation.

As previously stated,-in view of the fact i thatthese panel boards and the connections 'leadingtherefrom to the armatureand shunt fields of the motor are in common use a' further description of'said connections herein is omitted.

I particularly desire, however, to emphasize the fact that "while control of the motor which drivesthe blower of an exhaust pneumatic desp'atch tube'system by means of such-a cylinder asthat designatedQO and a connection thereto from the exhaust drum,

whereby to cut in or out out resistance in the motor shunt field, is already-known,

nevertheless itv has never been found practicable'heretofore, to the-bestf'of my knowledge, tofprovide such a device in connection with a vacuum pressuresystem, although it hasbeen known to use a panel board for the vacuum side and a second panel board for the pressure side whereby'to jointly control the motor from both sides.

Such a control has not been found to be altogether satisfactory since a number of lines onthe vacuum side may be simultaneously in operation while but perhaps one or even none will be in use on the pressure side of the blower.

' This provision, for-example, of a single panel with its connections whereby to control a vacuum-plenum system together with the valve combination shown and time element mechanism for the same, enables a ma-- terial reduction in cost of apparatus to be effected, together with increased efliciency; since the terminals at station B, for example, need be only of the simplest description and without valves, while the disposition of the blower, in effect, midway between the terminal 3 and the terminal 4:, permits of the use of a smaller motor than is ordinarily possible when the transmission of carriers in both directions is effected either solely by means of compressed air or solely by means of vacuum.

Having thus described my invention what I claim is:- p

"1. In a vacuum-plenum carrier despatch system, the combination of a normally dead transit tube having a receiving station substantially at one end thereof and a carrier delivery station at the other end thereof, an exhaust conduit therefor, a pressure transit tube, a compressed air supplying conduit therefor, means to rarefy the air in the first of said conduits and to compress air for the second of the same, and means adapted to substantially simultaneously establish communication between" said transit tubes and their respective conduits.

2. In a vacuum-plenumcarrier despatch system, the-combination of a normally dead transit tube having a receiving station substantially at one end thereof and a carrier delivery station at the other end thereof, an exhaust conduit therefor, 'a pressure transit tube, a compressed air supplying conduit therefor, means to rarefy the air in the first of said conduits and to compress air for the second of the same,valve mechanism adapted to substantially simultaneously establish.

communication 'between said transit tubesand their respective conduits, and means to control said valve mechanism.

"3. In a vacuum-plenum carrier despatch system,'the' combination of a normally dead transit tube having a receiving station sub stantially at one end thereof and a carrier delivery station at the other end thereof, an exhaust conduit therefor, a pressure transit tube, a compressed v air supplying conduit therefor, means to rarefy the air'in the" first of said conduits and to compress air for the system, the combination of a transit tube,

an exhaust conduit therefor, a pressure transit tube, a compressed air supplylng condu1t therefor, means to rarefy a1r lnthe first of said conduits and to compress air for the second of the same, two stations between whlch sa1d tubes extend, valve mechanism to substantially simultaneously establish communication between said transit tubes and their respective conduits, and means to control said valve mechanism from either of said stations.

5. In a vacuum-plenum carrier despatch system, the combination of a normally dead transit tube having a receiving station substantially at one end thereof and a carrier delivery station at the other end thereof, an exhaust conduit therefor, a pressure transit tube, a compressed air supplying conduit therefor, means to rarefy the air in the first of said conduits and to compress air for the second of the same, valve mechanism adapted to substantially simultaneously establish communication between said transit tubes and their respective conduits, time element means to automatically actuate said valve mechanism to disestablish said communication after the lapse of a period of time determined by said means, and means-to retime said time element means, to provide for the proper transmission of successively despatched carriers.

6. In a vacuum-plenum carrier despatch system, a transit tube extending between two stations and having in one of said stations at valved terminal and an exhaust conduit connected to this latter, whereby carriers may be propelled from the other of said stations substantially all the way to said first station by atmospheric pressure, the valve in said terminal being normally closed and the terminal of said tube at said other station beingnormally open, a second transit tube extending between said stations and having at the station first mentioned a valved terminal and a second conduit for supplying take" side and said exhaust conduit and between its outlet side and said second con duit,'and valve mechanism adapted to substan'tially simultaneously establish a flow of air from said second through said iio iao

first tube to its exhaust conduit and a corresponding flow of air from said second conduit through said second tube to saidlsecond station.

7. In a vacuum-plenum carrier despatch system, the combination of two normally their closed positions.

8. In a vacuum-plenum carrier despatch system, the combination of two normally dead transit tubes, one for; transmitting car-v riers by compressed air and the other by 1 air at substantially atmospheric pressureya pressure drum and a vacuum drum, connections between said drums and the respective tubes, valves. in each of said connections to control the flow of a1r through said tubes, and

electrically controlled means to set said valves simultaneously each in its open position.

,9. In a vacuum-plenum carrier despatch system, the combination of two normally dead transit tubes, one for transmitting carriers by compressed air and the other by air at substantially atmospheric pressure, a

pressure drum anda vacuum drum, connections between sald drums and the respectlve tubes, valves in each ofsald connectlons to control the flow of air through said tubes,

and means to set said valves simultaneously each in its open position.

10. In a vacuum-plenum carrier'despatch system, the combination of two normally dead transit tubes, one for transmitting carriers by compressed air and'the other by air at substantially atmospheric 7 pressure, a pressure drum and a vacuum drum, connections betweensaid drums and the respective tubes, valvesin each of said connections to control'the'flow of air through said tubes, means to set said valves in their open positions, and means to automatically close both of said valves substantially simultaneously.

11. In ineans'for controlling the flow of air through a vacuum-plenum carrier transmission system, a casing having in communication therewith a set of conduits for conveyingair at a pressure below that of the atmosphere and a second set of conduits for convey ng a1r above thatof the; atmosphere, connected valve parts, mounted on a com mon axislto control-the flow of air through saidconduits, pneumatic meansfor disp,os-

ing said'valve parts'intheir open positions, and time ,el ement mechanism for determining the period during atleast which said parts shall remain open and for thereafter normally insuring the return of said: valve parts to their conduit closing positions.

12. In means for controlling the flow of air through a vacuum-plenum carrier transmission system, a casing havingin communication therewith a set of conduits for con- 7 13. In a pneumaticdespatch system, the,

combination oftwo separate and normally dead transit tubes, a blower or pump, connections between the-exhaust side ofthe lat-. ter and one of said tubes and between the outlet side 01? said blower or pump and the other of said tubes, valve mechanism, nor

mally closing said connections, and means to automatically actuate said; mechanism to substantially simultaneously open said con? nections and to thereafterv automatically close the same. 7

14. In a pneumatic combination of two normally dead transit tubes, a blower or pump, a connectionfbetween the exhaust side of the latter and one despatch system, the

of said tubes, a connection between the out:

let side of said blower or pump and the other of said tubes, a valve infeach of said connections, means for substantiallylsimuL 'taneously opening said valves, and co-act; lng means for slmultaneously closlngsaid valves thereafter. V 15. In a pneumaticcarrier despatch sys tem, the combination of a transit tube with means, including a valve, for controlling the .fiow of a1r through said tube,.sa1d means having also a fluid pressure operated time large capacity, one wall of said chamber be ing formed by a movable partition, the said chamber, even when said partitionis in its innermost position therein, still vhavingfl-a relatively large capacity, means for normally-permitting only a seepage of air through a wall of said chambenandnormally closed auxiliary venting means'to afford communication between said chamber and air outsidethereof.

16. In a pneumatic carrier despatch system,,the' combination of a transit tube with means for establishing a carrier transmit ting flow of air through said tube, said means including a fluid pressure operated time element device in which is {a chamber of large capacity, one wall of said chamber being formed by a movable partition, the said element device in which is achamber-of chamber, even when said partition is in its In testimony whereof I have affixed my innermost position With respect to said signature, in the presence of tWo Witnesses.

chamber, still having a relatively largecapacity, means for normally permitting only a seepage of air through a Wall of said cham- ALBERT PEARSALL' her, and normally closed auxiliary venting Witnesses:

means to afford communication between said M. K. PORTER,

chamber and air outside thereof. E. M. JORDAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C." 

